A standard compound bow has a central body and a pair of limbs mounted at the ends of the body and limitedly pivotal thereon about parallel axes transverse to the body and limbs. Each limb is secured to the body inward from its pivot by a respective threaded bolt which is tightened to establish the relative angular position of the limb and the body. The outer ends of the limbs are interconnected by the bow string.
The draw weight, which determines the tension of the bow string, is changed by means of the bolts securing the limbs to the body. To increase the draw weight they are screwed in or tightened and to decrease it they are backed off.
It is absolutely essential that both limbs of the bow be set identically. Otherwise the center of the bow string will not move back perfectly on center when pulled back, and the bow will be out of tune and will not be accurate.
Hence the user of the bow must keep careful track of exactly how many times each limb bolt is turned, and must be sure that both limb bolts are turned the same number of turns. The settings for the bows must be recorded so they can be duplicated after loosening for storage or replacement of a bow string. Such a procedure is fairly onerous.